An ignition system of the above-described type is disclosed in U.S. Pat. No. 4,176,645. In the type of ignition system disclosed therein the closure angle varies relatively exactly according to the predetermined function as long as the speed of the engine (and the number of cylinders) results in an ignition repetition rate which is below a maximum value in which residual storage effects in the output stage become noticeable. If, however, this maximum value is exceeded, an undesired decrease in the closure angle relative to the desired closure angle results for the following reasons. In the known system, the closure angle control takes place by a charging and discharging of an integrator circuit during the time the interrupter switch is closed. Specifically, the charging of the integrator starts as the interrupter switch closes and continues until the current through the primary winding of the ignition coil reaches a predetermined limiting value. At this time a discharge of the integrator circuit commences. Above a particular ignition repetition rate, residual energy will still be stored in the ignition coil when the interrupter switch closes. This causes the current through the interrupter switch to jump to a value corresponding to this residual energy when the switch closes. The time for the current through the primary winding to reach the predetermined limiting value, that is the charging time of the integrator circuit is thus decreased, while the discharge time remains the same. The final value of voltage across the integrator circuit which in turn determines the threshold value of a threshold circuit controlling the interrupter switch therefore changes at high engine speeds for a given number of cylinders in a direction causing an unwanted decrease in the closure angle.